XAT 2022 — QA & DI Question 6
Number TheoryEasy
The sum of the cubes of two numbers is 128, while the sum of the reciprocals oftheir cubes is 2. What is the product of the squares of the numbers?
Answer & solution
- A
64
- B
256
16
- D
48
- E
32
Solution
Considering the two numbers to a, b :
We were given that:
a3 + b3 = 128
+ = 2
= 2 =
k = 64.
Hence a3 . b3 = 64
a*b = 4 and a2 .b2 = 16